The present invention is generally directed to medical devices, systems, and methods, particularly for cooling-induced remodeling of tissues. Embodiments of the invention include devices, systems, and methods for applying cryogenic cooling to dermatological tissues so as to selectively remodel one or more target tissues along and/or below an exposed surface of the skin. Embodiments may be employed for a variety of cosmetic conditions, optionally by inhibiting undesirable and/or unsightly effects on the skin (such as lines, wrinkles, or cellulite dimples) or on other surrounding tissue. Other embodiments may find use for a wide range of medical indications. The remodeling of the target tissue may achieve a desired change in its behavior or composition.
The desire to reshape various features of the human body to either correct a deformity or merely to enhance one's appearance is common. This is evidenced by the growing volume of cosmetic surgery procedures that are performed annually.
Many procedures are intended to change the surface appearance of the skin by reducing lines and wrinkles. Some of these procedures involve injecting fillers or stimulating collagen production. More recently, pharmacologically based therapies for wrinkle alleviation and other cosmetic applications have gained in popularity.
Botulinum toxin type A (BOTOX®) is an example of a pharmacologically based therapy used for cosmetic applications. It is typically injected into the facial muscles to block muscle contraction, resulting in temporary enervation or paralysis of the muscle. Once the muscle is disabled, the movement contributing to the formation of the undesirable wrinkle is temporarily eliminated. Another example of pharmaceutical cosmetic treatment is mesotherapy, where a cocktail of homeopathic medication, vitamins, and/or drugs approved for other indications is injected into the skin to deliver healing or corrective treatment to a specific area of the body. Various cocktails are intended to effect body sculpting and cellulite reduction by dissolving adipose tissue, or skin resurfacing via collagen enhancement. Development of non-pharmacologically based cosmetic treatments also continues. For example, endermology is a mechanical based therapy that utilizes vacuum suction to stretch or loosen fibrous connective tissues which are implicated in the dimpled appearance of cellulite.
While BOTOX® and/or mesotherapies may temporarily reduce lines and wrinkles, reduce fat, or provide other cosmetic benefits they are not without their drawbacks, particularly the dangers associated with injection of a known toxic substance into a patient, the potential dangers of injecting unknown and/or untested cocktails, and the like. Additionally, while the effects of endermology are not known to be potentially dangerous, they are brief and only mildly effective.
In light of the above, improved medical devices, systems, and methods utilizing a cryogenic approach to treating the tissue have been proposed, particularly for treatment of wrinkles, fat, cellulite, and other cosmetic defects. These new techniques can provide an alternative visual appearance improvement mechanism which may replace and/or compliment known bioactive and other cosmetic therapies, ideally allowing patients to decrease or eliminate the injection of toxins and harmful cocktails while providing similar or improved cosmetic results. These new techniques are also promising because they may be performed percutaneously using only local or no anesthetic with minimal or no cutting of the skin, no need for suturing or other closure methods, no extensive bandaging, and limited or no bruising or other factors contributing to extended recovery or patient “down time.” Additionally, cryogenic treatments are also desirable since they may be used in the treatment of other cosmetic and/or dermatological conditions (and potentially other target tissues), particularly where the treatments may be provided with greater accuracy and control, less collateral tissue injury and/or pain, and greater ease of use.
While these new cryogenic treatments are promising, the use of cryogenic fluids can be dangerous to the operator as well as the patient. Cryogenic fluids are often stored in a heater canister. Excessive heating of the canister could result in canister rupture and undesired fluid leakage. Additionally, many of these cryogenic systems are powered with electrical energy. A short circuit or other electrical failure could also result in unwanted canister heating and rupture. Rupture of the canister could result in dangerous projectiles flying through the air as well as cooling fluid leaking from the device and causing injury or unwanted results to the patient and/or physician. Therefore it would be desirable to provide cryogenic treatment devices and methods with additional safety features that can more carefully control storage and heating of the cryogenic fluid in the device. It would also be desirable if these safety features were also cost effective, easy to manufacture and operate.